Set explicitly packages for setuptools

[q0w]

Closes #1778

Contributor checklist

• Provided the tests for the changes.
• Assure PR title is short, clear, and good to be included in the user-oriented changelog

Maintainer checklist

• Assure one of these labels is present: backwards incompatible, feature, enhancement, deprecation, bug, dependency, docs or skip-changelog as they determine changelog listing.
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[q0w]

Fixed the error:
pyproject.toml: tool.mypy.overrides sections must be an array. Please make sure you are using double brackets like so: [[tool.mypy.overrides]]

[atugushev]

@q0w https://github.com/jazzband/pip-tools/actions/runs/3716280054/jobs/6302430284#step:6:177

2022-12-16T20:23:48.9975484Z /tmp/build-env-l170qp45/lib/python3.9/site-packages/setuptools/command/build_py.py:202: SetuptoolsDeprecationWarning:     Installing 'piptools._compat' as data is deprecated, please list it in `packages`.
2022-12-16T20:23:48.9976263Z     !!
2022-12-16T20:23:48.9976815Z 
2022-12-16T20:23:48.9976825Z 
2022-12-16T20:23:48.9977191Z     ############################
2022-12-16T20:23:48.9977667Z     # Package would be ignored #
2022-12-16T20:23:48.9978125Z     ############################
2022-12-16T20:23:48.9978686Z     Python recognizes 'piptools._compat' as an importable package,
2022-12-16T20:23:48.9979137Z     but it is not listed in the `packages` configuration of setuptools.
2022-12-16T20:23:48.9979392Z 
2022-12-16T20:23:48.9982523Z     'piptools._compat' has been automatically added to the distribution only
2022-12-16T20:23:48.9983000Z     because it may contain data files, but this behavior is likely to change
2022-12-16T20:23:48.9983470Z     in future versions of setuptools (and therefore is considered deprecated).
2022-12-16T20:23:48.9983713Z 
2022-12-16T20:23:48.9984031Z     Please make sure that 'piptools._compat' is included as a package by using
2022-12-16T20:23:48.9984520Z     the `packages` configuration field or the proper discovery methods
2022-12-16T20:23:48.9984944Z     (for example by using `find_namespace_packages(...)`/`find_namespace:`
2022-12-16T20:23:48.9985278Z     instead of `find_packages(...)`/`find:`).
2022-12-16T20:23:48.9985481Z 
2022-12-16T20:23:48.9985696Z     You can read more about "package discovery" and "data files" on setuptools
2022-12-16T20:23:48.9986050Z     documentation page.
2022-12-16T20:23:48.9986436Z 

[q0w]

@atugushev #1784